Eastsidepilot
Western Thunderer
Yes, they had a different profile designed so a brass sheet metal hanger could be hung on it to hold said pictures.Weren’t they picture rails rather than dado rails?
Nigel

And who can recall plinth blocks ? fitted at the base of door frame architraves where it meets the skirting. I retro fitted these in our previous premises originally built in 1900 where it had all been ripped out in the 60-70's.